1. Field of the Invention
The present invention relates to a portable apparatus and its method of protecting personal information stored in the portable apparatus and, more specifically, to a portable apparatus and its method of unlocking with the new personal identification number (PIN) code.
2. Description of the Related Art
As an example of portable apparatuses, a conventional mobile phone locks all or a part of its functions so as to protect personal information, such as phone numbers and e-mail addresses, or so as to prevent a person who is not the normal user from accessing contents or calling. For example, Japanese Patent Laid-open Application Publication No. 141087/2003 (hereinafter, referred to as “related art”) discloses a mobile phone which requires an input of a four-digit personal identification number (PIN) code to be unlocked.
However, the mobile phone described in the related art have a problem that its user is forced to perform a troublesome operation of inputting a four-digit PIN code in order to unlock it. With considering how frequent a mobile phone is used, this problem detract the convenience of the mobile phone largely.
In addition, the mobile phone described in the related art has a problem that it is required to input a four-digit PIN code equally for unlocking any function while the importance of the locked function may vary depending on the function.
On the other hand, in order to solve these problems, the digit number of a PIN code can simply be reduced. In this case, however, there is a security problem since a probability that a number which a person who is not the normal user randomly inputs coincides accidentally with the right PIN code increases exponentially depending on the reduced digit number.